阅读说明：本技术 用于空调室内机的控制方法及空调室内机 (Control method for air conditioner indoor unit and air conditioner indoor unit ) 是由 郝本华 孙婷 侯延慧 王珂 郭蕾 李红 王红 于 2019-11-15 设计创作，主要内容包括：本发明提供了一种用于空调室内机的控制方法及空调室内机。该空调室内机包括上部送风风机和位于上部送风风机下方的下部送风风机、以及将室外空气导流至上部送风风机和下部送风风机的上游的新风装置。控制方法包括：启动新风装置；获取用户身高；根据身高调节上部送风风机和下部送风风机的转速。本发明根据用户身高来调整上部送风风机和下部送风风机的转速,可将新鲜室外空气集中地吹送至用户的口鼻高度供用户呼吸,避免了室外空气在室内环境乱窜、浓度稀薄用户无法感知的情况发生。(The invention provides a control method for an air conditioner indoor unit and the air conditioner indoor unit. The indoor unit of the air conditioner comprises an upper air supply fan, a lower air supply fan and a fresh air device, wherein the lower air supply fan is positioned below the upper air supply fan, and the fresh air device guides outdoor air to the upper streams of the upper air supply fan and the lower air supply fan. The control method comprises the following steps: starting a fresh air device; acquiring the height of a user; the rotating speeds of the upper air supply fan and the lower air supply fan are adjusted according to the height. The invention adjusts the rotating speed of the upper air supply fan and the lower air supply fan according to the height of the user, can intensively blow fresh outdoor air to the mouth and nose height of the user for the user to breathe, and avoids the situation that the outdoor air is messy in the indoor environment and the concentration is thin and the user cannot sense the air.)

1. A control method for an air-conditioning indoor unit comprises an upper air supply fan, a lower air supply fan and a fresh air device, wherein the lower air supply fan is positioned below the upper air supply fan; it is characterized by comprising:

starting the fresh air device;

acquiring the height G of a user;

adjusting the rotating speeds of the upper air supply fan and the lower air supply fan according to the height G; wherein the step of adjusting the rotation speed of the upper air supply fan and the lower air supply fan according to the height G comprises:

when the height G is larger than the height L of the upper edge of the air outlet of the lower air supply fan and smaller than the height T of the lower edge of the air outlet of the upper air supply fan, and the difference | T-G | between the height G and the height of the lower edge of the air outlet of the upper air supply fan is smaller than or equal to the difference | G-L | between the height G and the height of the upper edge of the air outlet of the lower air supply fan, adjusting the rotating speed of the upper air supply fan to be a rated rotating speed, and adjusting the rotating speed of the lower air supply fan to be a rated rotating speed | G-L |/| T-L | times; and when the height difference | T-G | between the height of the body and the height of the lower edge of the air outlet of the upper air supply fan is larger than the height difference | G-L | between the height of the body and the height of the upper edge of the air outlet of the lower air supply fan, adjusting the rotating speed of the lower air supply fan to be a rated rotating speed, and adjusting the rotating speed of the upper air supply fan to be | T-G |/| T-L | times of the rated rotating speed.

2. The control method of claim 1, wherein the step of adjusting the rotational speeds of the upper and lower blower fans based on the height G comprises:

and under the condition that whether the height G is larger than or equal to the height T of the lower edge of the air outlet of the upper air supply fan or not, adjusting the rotating speed of the upper air supply fan to be a rated rotating speed, and turning off the lower air supply fan.

3. The control method of claim 1, wherein the step of adjusting the rotational speeds of the upper and lower blower fans based on the height G comprises:

and under the condition that whether the height G is less than or equal to the height L of the upper edge of the air outlet of the lower air supply fan or not, adjusting the rotating speed of the lower air supply fan to be a rated rotating speed, and turning off the upper air supply fan.

4. The control method according to claim 1, wherein vertical swing blades are respectively provided at air outlets of the upper and lower air supply fans, and the control method further comprises:

acquiring a user position;

and adjusting the swing angle of a vertical swing blade of the running air supply fan to blow the air flow to the user position.

5. The control method according to claim 1, further comprising:

acquiring the carbon dioxide concentration of the indoor environment;

judging whether the concentration of the carbon dioxide is greater than or equal to a preset concentration threshold value;

if yes, the fresh air device is started.

6. An indoor unit of an air conditioner, comprising:

an upper air supply fan and a lower air supply fan positioned below the upper air supply fan;

a fresh air device configured to guide outdoor air to the upstream of the upper and lower air supply fans; and

a controller configured to perform the control method of any one of claims 1-5.

7. An indoor unit of an air conditioner according to claim 6,

the fresh air device is arranged below the upper air supply fan and the lower air supply fan.

Technical Field

The invention relates to the field of air conditioning, in particular to a control method for an air conditioner indoor unit and the air conditioner indoor unit.

Background

In order to avoid the problem of air quality such as excessive carbon dioxide concentration caused by poor ventilation in the indoor environment, a fresh air device communicated with the outdoor environment is usually added in the indoor unit to introduce the outdoor air into the indoor environment. However, the existing air conditioner indoor unit with the fresh air device has the problems of thin concentration of the outdoor air blown out and poor user perception.

Disclosure of Invention

An object of the first aspect of the present invention is to overcome at least one technical drawback of the prior art and to provide a control method for an air conditioning indoor unit.

A further object of the first aspect of the invention is to reduce energy consumption.

It is another further object of the first aspect of the present invention to increase the volume of the introduced outdoor air.

An object of the second aspect of the present invention is to provide an indoor unit of an air conditioner having a fresh air device.

According to a first aspect of the present invention, there is provided a control method for an indoor unit of an air conditioner, the indoor unit of an air conditioner including an upper air supply fan and a lower air supply fan located below the upper air supply fan, and a fresh air device that guides outdoor air to upstream of the upper air supply fan and the lower air supply fan; it is characterized by comprising:

starting the fresh air device;

acquiring the height G of a user;

and adjusting the rotating speeds of the upper air supply fan and the lower air supply fan according to the height G.

Optionally, the step of adjusting the rotation speed of the upper air supply fan and the lower air supply fan according to the height G includes:

judging whether the height G is larger than or equal to the height T of the lower edge of the air outlet of the upper air supply fan;

and if so, adjusting the rotating speed of the upper air supply fan to be a rated rotating speed, and turning off the lower air supply fan.

Optionally, the step of adjusting the rotation speed of the upper air supply fan and the lower air supply fan according to the height G includes:

judging whether the height G is less than or equal to the height L of the upper edge of the air outlet of the lower air supply fan;

and if so, adjusting the rotating speed of the lower air supply fan to be a rated rotating speed, and turning off the upper air supply fan.

Optionally, the step of adjusting the rotation speed of the upper air supply fan and the lower air supply fan according to the height G includes:

judging whether the height G is greater than the height L of the upper edge of the air outlet of the lower air supply fan and less than the height T of the lower edge of the air outlet of the upper air supply fan;

if so, adjusting the rotating speed of the upper air supply fan to be the rated rotating speed which is multiplied by G-L/T-L, and adjusting the rotating speed of the lower air supply fan to be the rated rotating speed which is multiplied by T-G/T-L.

Optionally, the step of adjusting the rotation speed of the upper air supply fan and the lower air supply fan according to the height includes:

judging whether the height G is greater than the height L of the upper edge of the air outlet of the lower air supply fan and less than the height T of the lower edge of the air outlet of the upper air supply fan;

if so, when the height difference | T-G | between the height of the upper air supply fan and the height of the lower edge of the air outlet of the upper air supply fan is smaller than or equal to the height difference | G-L | between the height of the upper air supply fan and the height of the upper edge of the air outlet of the lower air supply fan, adjusting the rotating speed of the upper air supply fan to be a rated rotating speed, and adjusting the rotating speed of the lower air supply fan to be | G-L |/| T-L | times of the rated rotating speed; and when the height difference | T-G | between the height of the body and the height of the lower edge of the air outlet of the upper air supply fan is larger than the height difference | G-L | between the height of the body and the height of the upper edge of the air outlet of the lower air supply fan, adjusting the rotating speed of the lower air supply fan to be a rated rotating speed, and adjusting the rotating speed of the upper air supply fan to be | T-G |/| T-L | times of the rated rotating speed.

Optionally, the step of adjusting the rotation speed of the upper air supply fan and the lower air supply fan according to the height includes:

judging whether the height difference | T-G | between the height of the body and the height of the lower edge of the air outlet of the upper air supply fan is smaller than or equal to the height difference | G-L | between the height of the body and the height of the upper edge of the air outlet of the lower air supply fan;

if so, adjusting the rotating speed of the upper air supply fan to be a rated rotating speed, and turning off the lower air supply fan;

if not, adjusting the rotating speed of the lower air supply fan to be a rated rotating speed, and turning off the upper air supply fan.

Optionally, the air outlets of the upper air supply fan and the lower air supply fan are respectively provided with a vertical swing blade, and the control method further includes:

acquiring a user position;

and adjusting the swing angle of a vertical swing blade of the running air supply fan to blow the air flow to the user position.

Optionally, the control method further includes:

acquiring the carbon dioxide concentration of the indoor environment;

judging whether the concentration of the carbon dioxide is greater than or equal to a preset concentration threshold value;

if yes, the fresh air device is started.

According to a second aspect of the present invention, there is provided an air conditioning indoor unit, comprising:

an upper air supply fan and a lower air supply fan positioned below the upper air supply fan;

a fresh air device configured to guide outdoor air to the upstream of the upper and lower air supply fans; and

a controller configured to perform any of the control methods described above.

Optionally, the fresh air device is disposed below the upper air supply fan and the lower air supply fan.

The invention adjusts the rotating speed of the upper air supply fan and the lower air supply fan according to the height of the user, can intensively blow fresh outdoor air to the mouth and nose height of the user for the user to breathe, and avoids the situation that the outdoor air is messy in the indoor environment and the concentration is thin and the user cannot sense the air.

Furthermore, the invention only enables the upper air supply fan or the lower air supply fan to operate when the height of the user is higher than the lower edge of the upper air outlet or lower than the upper edge of the lower air outlet, and enables the upper air supply fan and the lower air supply fan to operate simultaneously when the height of the user is between the upper air outlet and the lower air outlet, thereby saving energy and electricity and reasonably distributing outdoor air in an optimal flow field.

Particularly, when the height of a user is between the upper air outlet and the lower air outlet, the upper air supply fan and the lower air supply fan can be operated simultaneously, outdoor air can be forced to flow upwards by the air supply fan with low rotating speed and is sucked by the air supply fan with high rotating speed, energy is saved, the whole air volume of the introduced outdoor air is improved, and the service life of the fan is prolonged.

The above and other objects, advantages and features of the present invention will become more apparent to those skilled in the art from the following detailed description of specific embodiments thereof, taken in conjunction with the accompanying drawings.

Drawings

Some specific embodiments of the invention will be described in detail hereinafter, by way of illustration and not limitation, with reference to the accompanying drawings. The same reference numbers in the drawings identify the same or similar elements or components. Those skilled in the art will appreciate that the drawings are not necessarily drawn to scale. In the drawings:

fig. 1 is a schematic cross-sectional view of an air conditioning indoor unit according to an embodiment of the present invention;

fig. 2 is a flowchart of a control method for an air conditioning indoor unit according to an embodiment of the present invention;

fig. 3 is a detailed flowchart of a control method for an air conditioning indoor unit according to the present invention.

Detailed Description

Fig. 1 is a schematic cross-sectional view of an air conditioning indoor unit 100 according to one embodiment of the present invention. Referring to fig. 1, the indoor unit 100 of the air conditioner may include a cabinet 110, an upper supply fan 120, and a lower supply fan 130 positioned below the upper supply fan 120, an indoor heat exchanger, a fresh air device, and a controller (not shown) storing a computer program.

The cabinet 110 may be provided with a cabinet inlet 111 through which gas flows in, and an upper outlet 112 and a lower outlet 113 through which gas flows out. The housing inlet 111 may be opened at a rear wall of the housing 110, and the upper outlet 112 and the lower outlet 113 may be opened at a front wall of the housing 110.

The upper and lower blower fans 120 and 130 may be disposed in the cabinet 110 and configured to draw air from the surrounding environment of the cabinet inlet 111 and to force the air to flow toward the upper and lower outlets 112 and 113, respectively.

The models of the upper and lower blower fans 120 and 130 may be the same. The upper and lower blower fans 120 and 130 may be both centrifugal fans to increase the amount of air supplied to the indoor unit 100.

The indoor heat exchanger may include an upper heat exchanger 140 and a lower heat exchanger 150 disposed below the upper heat exchanger 140. The upper heat exchanger 140 and the lower heat exchanger 150 may be respectively disposed on an intake air flow path between the cabinet air intake 111 and the upper air-supply blower 120, and between the cabinet air intake 111 and the lower air-supply blower 130, and exchange heat with air flowing therethrough to change the temperature of the air flowing therethrough into heat-exchange air.

The fresh air device can include a fresh air duct 161 having a fresh air inlet and a fresh air outlet and a fresh air impeller 162 arranged in the fresh air duct 161, wherein the fresh air inlet can be communicated with the outdoor environment through a fresh air pipeline 170, and the fresh air impeller 162 can be arranged to suck outdoor air through the fresh air inlet and make the outdoor air flow to the upstream of the indoor heat exchanger through the fresh air duct 161, so as to exchange heat with the indoor heat exchanger.

The fresh air device may be disposed below the upper and lower air supply fans 120 and 130. The indoor unit 100 may further include an air guide cover plate 180, and the air guide cover plate 180 may be disposed at a rear side of the rear wall of the cabinet 110 and communicate with a fresh air outlet of the fresh air device and a bottom area of the cabinet air inlet 111 to guide outdoor air to an upstream of the indoor heat exchanger.

Particularly, the controller may be configured to obtain the height G of the user after the fresh air device is started, and adjust the rotation speeds of the upper air supply fan 120 and the lower air supply fan 130 according to the height G of the user, so as to intensively blow fresh outdoor air to the mouth and nose height of the user for the user to breathe, thereby preventing the outdoor air from flowing in a messy indoor environment and being low in concentration, which is not sensed by the user.

In some embodiments, the controller may be configured to adjust the rotation speed of the upper blower fan 120 to a rated rotation speed and shut down the lower blower fan 130 when the height G is greater than or equal to the height T of the lower edge of the air outlet of the upper blower fan 120, so as to save energy and allow the user to breathe more fresh outdoor air.

The controller may be configured to adjust the rotation speed of the lower air supply fan 130 to a rated rotation speed and shut down the upper air supply fan 120 when the height G is less than or equal to the height L of the upper edge of the air outlet of the lower air supply fan 130, so that the user breathes more fresh outdoor air while saving energy.

The controller can be configured to adjust the rotating speed of the upper air supply fan 120 to be the rated rotating speed of | G-L |/| T-L |, times, and the rotating speed of the lower air supply fan 130 to be the rated rotating speed of | T-G |/| T-L |, times when the height G is larger than the height L of the upper edge of the air outlet of the lower air supply fan 130 and smaller than the height T of the lower edge of the air outlet of the upper air supply fan 120, so that energy is saved, a user can breathe more fresh outdoor air, the integral air volume of the introduced outdoor air is increased, and the service life of the fan is prolonged.

In other embodiments, the difference from the previous embodiment is that in the case that the height G is greater than the height L of the upper edge of the outlet of the lower blower 130 and less than the height T of the lower edge of the outlet of the upper blower 120, the controller may be configured to adjust the rotation speed of the upper blower 120 to the rated rotation speed and the rotation speed of the lower blower 130 to the rated rotation speed | G-L |/| T-L | times when the difference | T-G | between the height and the height of the lower edge of the outlet of the upper blower 120 is less than or equal to the difference | G-L | between the height and the height of the upper edge of the outlet of the lower blower 130; when the height difference | T-G | between the height of the lower edge of the air outlet of the upper air supply fan 120 and the height difference | G-L | between the height of the lower edge of the air outlet of the upper air supply fan 120 and the height of the upper edge of the air outlet of the lower air supply fan 130 is larger than the height of the upper edge of the air outlet of the lower air supply fan 130, the rotating speed of the lower air supply fan 130 is adjusted to be the rated rotating speed, and the rotating speed of the upper air supply fan 120 is adjusted to be the rated rotating speed which is | T-G |/| T-L | times, so that energy is saved, a user can breathe more fresh outdoor air, and the whole air volume of the introduced outdoor air is further improved.

In still other embodiments, the controller may be configured to adjust the rotation speed of the upper blower fan 120 to a rated rotation speed and shut down the lower blower fan 130 when a difference | T-G | between a height of the upper blower fan 120 and a height of the lower edge of the outlet is equal to or less than a height difference | G-L | between the height of the lower edge of the outlet of the lower blower fan 130; when the height difference | T-G | between the height of the lower edge of the air outlet of the upper air supply fan 120 and the height difference | G-L | between the height of the lower edge of the air outlet of the lower air supply fan 130 is greater than the height difference | G-L | between the height of the upper edge of the air outlet of the lower air supply fan 130, the rotating speed of the lower air supply fan 130 is adjusted to be the rated rotating speed, and the upper air supply fan 120 is turned off, so that the user can breathe more fresh outdoor air and save energy.

In some embodiments, a vertical swing blade 125 and a vertical swing blade 135 are respectively provided at the air outlets of the upper and lower air supply fans 120 and 130 for adjusting the flow direction of the air flow in the lateral direction.

The controller can be configured to acquire the position of the user after the fresh air device is started, and adjust the swing angle of the vertical swing blade of the running air supply fan to blow the airflow to the position of the user, so that the user can breathe more fresh outdoor air through secondary positioning.

The indoor unit 100 of the air conditioner may further include an infrared induction camera 190. The infrared sensing camera 190 may be fixed to an upper portion of the cabinet 110 and configured to sense the height and position of the user.

In some embodiments, the controller may be configured to activate the fresh air device based on a carbon dioxide concentration of the indoor environment. Specifically, when the carbon dioxide concentration of the indoor environment is greater than or equal to the preset concentration threshold value, the fresh air device is started to ventilate the indoor environment. The predetermined concentration threshold may be 800-1000 PPM, such as 800PPM, 900PPM, or 1000 PPM.

The controller may be further configured to activate the fresh air device based on an air quality index of the outdoor environment based on the carbon dioxide concentration of the indoor environment to prevent the indoor environment from being contaminated. Specifically, when the carbon dioxide concentration of the indoor environment is greater than or equal to a preset concentration threshold value and the air quality index of the outdoor environment is less than or equal to a preset quality threshold value, the fresh air device is started. The air quality index may be determined according to GB 3095-2012. The predetermined quality threshold may be 50 to 100, such as 50, 70, 80 or 100.

The controller may be configured to turn off the fresh air device and stop ventilating the indoor environment when the concentration of carbon dioxide in the indoor environment is less than a preset concentration threshold.

Fig. 2 is a flowchart of a control method for the air-conditioning indoor unit 100 according to an embodiment of the present invention. Referring to fig. 2, the control method for the air conditioning indoor unit 100 performed by the controller according to any one of the above embodiments of the present invention may include the steps of:

step S202: the fresh air device is started.

Step S204: and acquiring the height of the user. In this step, the height of the user can be sensed by the infrared sensing camera 190.

Step S206: the rotating speeds of the upper air supply fan 120 and the lower air supply fan 130 are adjusted according to the height of a user, so that fresh outdoor air is intensively blown to the mouth and nose height of the user for the user to breathe, and the situation that the outdoor air is mixed in the indoor environment and the concentration is thin and the user cannot sense the air is avoided.

In some embodiments, step S206 may include the steps of:

judging whether the height G is greater than or equal to the height T of the lower edge of the air outlet of the upper air supply fan 120;

if so, adjusting the rotating speed of the upper air supply fan 120 to be the rated rotating speed, and turning off the lower air supply fan 130 so as to enable the user to breathe more fresh outdoor air while saving energy;

if not, when the height G is less than or equal to the height L of the upper edge of the air outlet of the lower air supply fan 130, adjusting the rotating speed of the lower air supply fan 130 to be a rated rotating speed, and turning off the upper air supply fan 120, so that the user can breathe more fresh outdoor air while saving energy; when the height G is larger than the height L of the upper edge of the air outlet of the lower air supply fan 130, the rotating speed of the upper air supply fan 120 is adjusted to be the rated rotating speed which is multiplied by G-L/T-L, and the rotating speed of the lower air supply fan 130 is adjusted to be the rated rotating speed which is multiplied by T-G/T-L, so that the energy is saved, a user can breathe more fresh outdoor air, the integral air volume of the introduced outdoor air is increased, and the service life of the fan is prolonged.

In other embodiments, step S206 may include the steps of:

judging whether the height G is greater than or equal to the height T of the lower edge of the air outlet of the upper air supply fan 120;

if so, adjusting the rotating speed of the upper air supply fan 120 to be the rated rotating speed, and turning off the lower air supply fan 130 so as to enable the user to breathe more fresh outdoor air while saving energy;

if not, when the height G is less than or equal to the height L of the upper edge of the air outlet of the lower air supply fan 130, adjusting the rotating speed of the lower air supply fan 130 to be a rated rotating speed, and turning off the upper air supply fan 120, so that the user can breathe more fresh outdoor air while saving energy; when the height G is larger than the height L of the upper edge of the air outlet of the lower air supply fan 130 and the difference | T-G | between the height and the height of the lower edge of the air outlet of the upper air supply fan 120 is smaller than or equal to the difference | G-L | between the height and the height of the upper edge of the air outlet of the lower air supply fan 130, the rotating speed of the upper air supply fan 120 is adjusted to be the rated rotating speed, and the rotating speed of the lower air supply fan 130 is adjusted to be | G-L |/| T-L | times of the rated rotating speed; when the height G is greater than the height L of the upper edge of the air outlet of the lower air supply fan 130 and the difference | T-G | between the height and the height of the lower edge of the air outlet of the upper air supply fan 120 is greater than the difference | G-L | between the height and the height of the upper edge of the air outlet of the lower air supply fan 130, the rotating speed of the lower air supply fan 130 is adjusted to be the rated rotating speed, and the rotating speed of the upper air supply fan 120 is adjusted to be the rated rotating speed | T-G |/| T-L | times, so that energy is saved, a user can breathe more fresh outdoor air, and the whole air volume of the introduced outdoor air is further increased.

In still other embodiments, step S206 may include the following steps:

judging whether the height difference | T-G | between the height of the height and the lower edge of the air outlet of the upper air supply fan 120 is smaller than or equal to the height difference | G-L | between the height of the height and the upper edge of the air outlet of the lower air supply fan 130;

if so, adjusting the rotating speed of the upper air supply fan 120 to be the rated rotating speed, and turning off the lower air supply fan 130;

if not, the rotating speed of the lower air supply fan 130 is adjusted to be the rated rotating speed, and the upper air supply fan 120 is turned off, so that the user can breathe more fresh outdoor air and save energy.

In some embodiments, the control method of the present invention may further include:

acquiring a user position (wherein the user position can be sensed by the infrared sensing camera 190);

the swing angle of the vertical swing blade of the running air supply fan is adjusted to blow the air flow to the position of the user, so that the user can breathe more fresh outdoor air through secondary positioning.

In some embodiments, before step S202, the control method of the present invention may further include:

acquiring the carbon dioxide concentration of an indoor environment and the air quality index of an outdoor environment;

judging whether the carbon dioxide concentration of the indoor environment is greater than or equal to a preset concentration threshold value and the air quality index of the outdoor environment is less than or equal to a preset quality threshold value; the preset concentration threshold value can be 800-1000 PPM, and the air quality index can be determined according to GB 3095-2012;

if yes, the fresh air device is started.

Fig. 3 is a detailed flowchart of a control method for the air-conditioning indoor unit 100 according to the present invention. Referring to fig. 3, the control method for the indoor unit 100 of an air conditioner of the present invention may include the following detailed steps:

step S302: and acquiring the carbon dioxide concentration of the indoor environment.

Step S304: and judging whether the carbon dioxide concentration of the indoor environment is greater than or equal to a preset concentration threshold value or not. If yes, go to step S306; if not, the process returns to step S302.

Step S306: an air quality index of an outdoor environment is obtained.

Step S308: and judging whether the air quality index of the outdoor environment is less than or equal to a preset quality threshold value. If yes, go to step S310; if not, the process returns to step S302.

Step S310: the fresh air device is started.

Step S312: and acquiring the height G and the position of the user.

Step S314: and judging whether the height G is more than or equal to the height T of the lower edge of the air outlet of the upper air supply fan 120. If yes, go to step S316; if not, go to step S318.

Step S316: the rotational speed of the upper air supply fan 120 is adjusted to a rated rotational speed, and the swing angle of the vertical swing blade is adjusted to blow the air flow to the user position, and the lower air supply fan 130 is turned off. Step S324 is performed.

Step S318: and judging whether the height G is less than or equal to the height L of the upper edge of the air outlet of the lower air supply fan 130. If yes, go to step S320; if not, go to step S322.

Step S320: the rotational speed of the lower air supply fan 130 is adjusted to a rated rotational speed, and the swing angle of the vertical swing blade is adjusted to blow the air flow to the user position, and the upper air supply fan 120 is turned off. Step S324 is performed.

Step S322: the rotational speed of the upper air supply fan 120 is adjusted to be a rated rotational speed | G-L |/| T-L | times, and the rotational speed of the lower air supply fan 130 is adjusted to be a rated rotational speed | T-G |/| T-L | times. Step S324 is performed.

Step S324: and acquiring the carbon dioxide concentration of the indoor environment.

Step S326: and judging whether the concentration of the carbon dioxide is less than a preset concentration threshold value. If yes, go to step S328; if not, the process returns to step S312 and step S324.

Step S328: the fresh air device is closed.

Thus, it should be appreciated by those skilled in the art that while a number of exemplary embodiments of the invention have been illustrated and described in detail herein, many other variations or modifications consistent with the principles of the invention may be directly determined or derived from the disclosure of the present invention without departing from the spirit and scope of the invention. Accordingly, the scope of the invention should be understood and interpreted to cover all such other variations or modifications.